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20202
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Subject: NITROGENO × Publisher: Springer ×

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Now showing 1 - 2 of 2
  • Artículo de revista
    Production and establishment techniques for the restoration of Nothofagus alessandrii, an endangered keystone species in a Mediterranean forest
    Ruil (Nothofagus alessandrii) is an endangered keystone species from the Mediterranean climate zone of Chile. Ruil’s fragile state of conservation urges development of restoration programs, but specific protocols for nursery production and field establishment that ensure plant survival are largely unknown. Therefore, we examined the effect on nitrogen (N) fertilization and container size during nursery production in combination with the use of mesh shelters after outplanting on survival and growth during the first growing season in the field. First year outplanting survival of nursery-grown container seedlings was enhanced when seedlings were given nitrogen (N) during nursery production and deployed with mesh tree shelters in the field. The volume of the container had no effect on outplanting survival and growth. Increasing N from zero to 200 mg N L−1 provided sufficient N levels, resulting in increased seedling height, root-collar diameter, shoot biomass, and total seedling N and phosphorous concentrations. Additional N provided by the 400 and 600 mg N L−1 treatments underwent luxury consumption by the seedlings with no further benefits in field performance. Improved growth in the nursery, along with the use of mesh tree shelters after outplanting, especially during the typical summer drought, may be responsible for increased survival during the first growing season. Increasing the performance of nursery-grown ruil seedlings is essential to restoring this endangered, vulnerable, and foundation species within the highly biodiverse, yet seriously threatened endemic Maulino Costero Forest of the Mediterranean climate of central Chile.
    Acevedo Tapia, Manuel-Álvarez, Carolina-Cartes Rodríguez, Eduardo-Dumroese, R. Kasten-González Ortega, Marta
    2020
  • Artículo de revista
    Nitrogen loading of Eucalyptus globulus seedlings: nutritional dynamics and influence on morphology and root growth potential
    Achieving successful outplanting of trees on increasingly harsher sites is a global concern. In Chile, for example, new Eucalyptus globulus plantations are being targeted to poorer, low fertility sites where additional stresses often negatively affect seedling performance during the first field season. Nitrogen-loading during the later stages of nursery production can, however, significantly improve seedling physiological performance on harsher sites by increasing plant growth and nutrient storage reserves for subsequent root growth after outplanting. Maximizing these benefits, and applying the concept of loading throughout the entire crop cycle, requires a better understanding of nitrogen (N) dynamics. Thus, for container E. globulus, considered one of the most important plantation species worldwide, we evaluated the effects of increasing N supply (50 to 600 mg N L−1) on seedling morphological traits, biomass production, root growth potential, and foliar N. After 15 weeks of N application, seedlings showed an increase in all growth variables evaluated up to 300 mg N L−1, whereas higher rates allowed luxury consumption. Modeling growth responses revealed, however, an apparent ammonium antagonism with other macronutrient cations suggests that high rates of this N-form may negate the potential benefits of N-loading, or that other modifications to the fertilizer solution may promote additional growth at higher N rates. Foliar N concentration, which was easily and accurately measured with a leaf chlorophyll meter, showed a gradient from basal to apical leaves suggesting a strong translocation of N in E. globulus seedlings. Our results suggest nursery management that supplies 300 mg L−1 of N through the entire growing season could improve seedling nutritional status, morphological attributes, and growth of new roots, attributes that may improve establishment on low fertility sites.
    Acevedo Tapia, Manuel-Rubilar, Rafael-Dumroese, R. Kasten-Ovalle, Juan F.-Sandoval, Simón-Chassin-Trubert Fuentealba, Rodrigo Andrés
    2020